Ensure valid cost table is used
Ensure valid cost table is used

BUG=aomedia:685

Change-Id: I592016faeb4645cf43c599e0e2e11127e2a17c4e

GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom,GrokImageCompression/aom